This supplement is a direct extension of the original project titled "Cortical control of a dexterous prosthetic hand". Individuals with tetraplegia due to spinal cord injury will participate in a month-long study with the advantage of demonstrating the effectiveness of concerted real-time electrocorticography (ECoG) -based brain-controlled interface (BCI) training. This BCI training will be conducted in a well-defined learning paradigm leading to the control of an anthropomorphic dexterous prosthetic arm and hand system. Custom-made subdural ECoG electrode grids, implanted over the arm and hand area of the motor cortex, will remain in place for one month. The participants will be trained to control the prosthetic arm using a "shared-mode control" paradigm which essentially blends control signals derived from cortical activity with an ideal control signal generated by an automatic robot control system. By gradually tuning down the shared-mode ratio, i.e., the level of computer assist, the subject is able to consistently experience a controlled degree of success in completing reach to grasp tasks while the actual difficulty of the task changes to reflect increasing device control skill. We expect that participants will learn to control hand translation, rotation, and grasping for a total of 9 degrees of freedom. Over the duration of training, we expect that their performance will improve and that they will be able to complete tasks related to activities of daily living with at least 90% success. Further, we will characterize the effect of shared-mode control on cortical plasticity as captured by ECoG recording. We expect that the depth of modulation (variation in ECoG signal feature activities across different prosthetic arm movements) will increase over time to optimize performance in the shared-mode BCI training paradigm. This proposed study takes the important step of transferring BCI research completed in non-human primates and humans undergoing ECoG monitoring for intractable epilepsy to an end-user population. The primary focus of this proposal relates to control of reach and grasp activities. Restoring these functions with an advanced prosthetic limb will have a significant impact on the quality of life for individuals with upper limb impairments. PUBLIC HEALTH RELEVANCE: The goal of this project is to demonstrate that individuals with spinal cord injury can achieve robust electrocorticography (ECoG) -based brain control of an anthropomorphic prosthetic arm and hand. Successful completion of this project will significantly advance research in using brain-computer interface technology to enhance function and improve the quality of life for individuals with spinal cord injury.